Numerous attempts have been made to produce satisfactory filtering devices for removing objectionable constituents from the exhaust gases of internal combustion engines. The filters of the prior art have been subject to two common mechanical faults, namely, channeling of the gases in the filter element whereby intimate contact between the gases to be filtered and the filtering substance is not achieved and a deterioration of the structure of the gas filtering device due to the corrosive effects of the exhaust gases at the high temperatures involved. The present invention achieves a remedy of both of these prior art difficulties by a novel form of construction of the interior of the filtering device in combination with a novel filter cartridge. In the present invention a spacing member which spaces the filter cartridge from the exterior casing of the device is designed to protect the exterior casing and at the same time to distribute the gases to be filtered in the most efficient manner through a specially designed filter cartridge which is gas permeable from end to end and radially.